Fig. 3

Dose-response effect of protea-some inhibitors on wtPS1-expressing HEK293 cells. Stably transfected HEK293 cells expressing wtPS1 were incubated for 16 hr with the indicated concentrations of lactacystin or Z-IE(Ot-Bu)A-Leucinal, then cells were lysed and immunoreactivity of HMW-PS1, LMW-PS1, and CTF-PS1 was revealed with αPS1Loop antibody (A) as described in Materials and Methods. Histograms in B represent the densitometric analysis of HMW-PS1 (black bars) and LMW-PS1 (white bars) immunoreactivity and are the means ± S.E.M. of three independent experiments.